The present invention relates to crystalline silicates of novel structure and a process for the production of said crystalline silicates. More particularly, the present invention relates to crystalline silicates having a novel structure which can be effectively used as catalysts for various chemical reactions, and also to a process for efficiently producing said crystalline silicates. These crystalline silicates are called herein crystalline silicates (ISI-4).
A number of crystalline silicates, natural or synthetic, have heretofore been known, and various processes for the production thereof have been proposed. In general, these crystalline silicates are produced by preparing an aqueous mixture consisting of a silica source, an alumina source, and an alkali metal source and, thereafter, subjecting the aqueous mixture to a hydrothermal reaction.
Recently, a method has been developed to produce crystalline silicate zeolites with a specific structure by adding organic compounds exemplified by tetrapropylammonium bromide to the aqueous mixture. For example, Japanese Patent Application Laid-Open No. 134517/81 describes that ZSM-5 zeolite is produced by adding diols to the aqueous mixture. Also, Japanese Patent Application Laid-Open No. 107499/79 describes that crystalline aluminosilicate zeolites with specific structure are produced by adding monoethanolamine. Although the structure is not shown, examination of the examples of Japanese Patent Application Laid-Open No. 17920/81 in which nearly the same conditions as in Japanese Patent Application Laid-Open No. 107499/79 are employed reveals that the crystalline aluminosilicate zeolites are similar to ZSM-5 zeolite.
As a result of extensive investigations to develop silicates with a novel composition and a novel crystalline structure, it has been found that, although organic compounds such as monoethanolamine are added in small amounts in relation to the silica source or alumina source in conventional methods, if ethylene glycol or monoethanolamine of the organic compounds is added in such a large amount as to be a solvent, crystalline silicates with a novel structure are obtained.